Don't mean to be rude at all.. Do you think that if Americans live in Hawaii, their English skills would deteriorate because English spoken there is not sophisticated due to large number of non-native speakers?

I was born and raised in Hawaii and I speak English very well.  Granted I've been away from Hawaii for decades but I always spoke well.  Yes there are many there who speak "pigeon English", when living there, at times I did as well.  The think is, my parents insisted that we spoke "proper English " at home.